1. Field of the Invention
The invention relates to a system for providing a modem user with a plot of the amplitude response of a channel such as a telephone line in the frequency band occupied by the modem signal without interrupting or otherwise affecting data signal traffic through the modem.
2. Description of the Prior Art
One of the many channel parameters affecting modem performance is the amplitude spectral characteristic of the channel. Severe band edge rolloff and ripples in the amplitude response can impair modem performance. Given spectrum information, the user can take appropriate action such as contacting the telephone company to correct telephone line problems.
In order to obtain the amplitude characteristics of a channel such as a telephone line, the modems on the line must be removed and test equipment installed at both ends of the line to make the meauurement. This method interrupts customer data traffic for the duration of the test.